LeetCode-M-Insertion Sort List

题意

解法

实现

/**
* Definition for singly-linked list.
* struct ListNode {
*     int val;
*     ListNode *next;
*     ListNode(int x) : val(x), next(NULL) {}
* };
*/
class Solution {
public:
ListNode* insertionSortList(ListNode* head) {
if(head == NULL || head->next == NULL) return head;
ListNode* tail = head;
ListNode* next = head->next;
while(next != NULL){
ListNode* pre = NULL;
ListNode* cur = head;
while(cur != next && cur->val < next->val){
pre = cur;
cur = cur->next;
}
if(cur == next) {
tail = next;
}else if(pre == NULL){
tail->next = next->next;
next->next = head;
head = next;
}else{
tail->next = next->next;
next->next = pre->next;
pre->next = next;
}
next = tail->next;
}
return head;
}
};